The macrolide family comprises a large number of well-known antibiotics which exhibit significant physiological activites. The aims of this project are to establish general schemes for the synthesis of several representative "polyoxo" macrolide antibiotics and also to develop new methods applicable to vital synthetic transformations. The macrolides selected as major synthetic targets for the current year are: (a) The 14-membered metabolite, 6-desoxyerythronolide B, and (b) the 16-membered homologs, leucomycin A1 and tylosin. In addition to the synthesis of these antibiotics, our major interest continues to focus on the exploration of newer methods of constructing the beta-hydroxy-alpha-methylcarbonyl system with enantio- and diastereoselections much higher than those attained last year. The system constitutes a basic unit present in the antibiotics. This year's work is highlighted with the successful synthesis of 6-desoxyerythronolide B, which has been executed with remarkable stereoselection through the extensive use of newly developed reagents. Leucomycin A1 also yielded to synthesis.